Subject: Fwd: Qu. of Cruickshank
Date: 12 Mar 2002 12:01:17 +0200
From: "Peter Witbooi"
The following reference is not quite to the point
but might just be helpful. On the question by Jim Cruickshank below,
in the article,
Daniel Quillen, Higher Algebraic K-theory I, in:
Springer-Verlag Lecture Notes in Mathematics 341,
Algebraic K-Theory I - Higher K-theories, pp85-147,
the category QM, for an exact category M (p100), has composition defined
in a manner dual to that of Cruickshank.
Sincerely,
Peter Witbooi
Department of Mathematics
University of the Western Cape
Private Bag X17
7535 Bellville
South Africa
=======
Subject: question for the topology list
Date: Mon, 11 Mar 2002 16:36:21 +0000
From: james cruickshank
I have a question for the topology list:
I have recently been thinking about the following category in connection
with knot invariants: The objects are groups. A morphism G_1 --> G_2
is diagram G_1 --> H <-- G_2. Two morphisms are composed
by taking pushout. I am sure that I have seen this category mentioned
somewhere but I can't remember where. Can anyone supply a reference
that would contain information about this category?
Thanks
Jim Cruickshank.